Allometry in Physarum plasmodium during free locomotion: size versus shape, speed and rhythm

摘要: ABSTRACT Physarum plasmodium is a giant unicellular organism whose length can vary by more than three orders of magnitude. Using plasmodia ranging in size from 100 μm to 10 cm, we investigated the dependency their thickness distributions and locomotion speeds during free locomotion. (1) In longitudinal direction, thickest close front, decreases exponentially towards rear. The slenderness ratio varies with body according power law, such that large are long flat, whereas small short thick. (2) mean speed proportional maximum frontal part. By conducting dimensional analysis, possible physical models discussed. (3) intrinsic period oscillation, which related shuttle streaming (period 1–2 min), increases logarithmically size. (4) Various characteristics exhibit size-independent, long-period (20±10 min) oscillations, including speed, shape oscillation period. These variations closely coupled formation entire cell shape, undulation along axis timing branching tip. Based on these experimental results those reported previously, propose simple mathematical model for